KR102326325B1 - Friction saw for cutting high maganese steel - Google Patents

Abstract

A friction saw for cutting high manganese steel includes a base made of a disk, and a plurality of saw blades integrally formed with the base and continuously arranged on a circumferential surface of the base. Each of the plurality of saw blades has a front surface, a rear surface, a top surface, and a pair of inclined surfaces, and includes a pair of hardening areas in contact with both ends of the front surface, the rear surface and the top surface.

Description

Friction saw for cutting high manganese steel {FRICTION SAW FOR CUTTING HIGH MAGANESE STEEL}

The present invention relates to a friction saw for cutting steel, and more particularly, to a friction saw for cutting high manganese steel pipe.

Structural steel materials are being developed in the direction of increasing strength and rigidity, which leads to advantages such as reduction in the amount of steel used and improvement in the safety of structural materials. However, as the strength, rigidity, and toughness of steel materials increase, forming, welding, processing, etc. become difficult to cope with existing equipment when manufacturing products using them, and in particular, cutting operations are becoming very difficult.

For example, conventional carbon steel is cut at high speed using a cutting tool made of carbide. In this case, the cutting surface is clean and cutting chips can be easily discharged by using the method of digging a groove on the saw blade.

However, high manganese steel has high toughness and is very tough, so when cut in the same way as carbon steel, the cut surface is not clean, such as a tear in the cut surface, and the cutting tool is damaged after being cut in half. occurs Therefore, the development of a new cutting mechanism suitable for the characteristics of high manganese steel is required.

An object of the present invention is to provide a high manganese steel material, for example, a friction saw for cutting high manganese steel that can cut a high manganese steel pipe cleanly without defects.

A friction saw for cutting high manganese steel according to an embodiment of the present invention includes a base made of a disc, and a plurality of saw blades integrally formed with the base and arranged continuously on the circumferential surface of the base. Each of the plurality of saw blades has a front surface, a rear surface, a top surface, and a pair of inclined surfaces, and includes a pair of hardening areas in contact with both ends of the front surface, the rear surface and the top surface.

Each of the plurality of saw blades may be formed of a left-right symmetric triangle, and a vertex and a left-right lower point may have a curvature of a preset radius. Each of the pair of hardened areas may have a depth that gradually increases from the base toward the top surface, and the maximum depth of each of the pair of hardened areas may be less than or equal to half the thickness of the saw blade.

Each of the pair of curing regions may occupy at least half of each of the front and rear surfaces on the upper side of the front surface and the upper side of the rear surface in contact with the top surface. The maximum depth of each of the pair of hardened areas may be between 0.05 and 0.25 times the saw blade thickness. The pair of hardened areas may have a hardness of 800 to 890 Hv, and the remaining areas of the saw blade excluding the hardened area may have a hardness of 350 to 420 Hv.

A method for manufacturing a friction saw for cutting high manganese steel according to an embodiment of the present invention comprises: a processing step of machining a friction saw including a disk-shaped base and a plurality of saw blades continuously arranged on a circumferential surface of the base; and a laser heat treatment step of irradiating a laser to the front and rear surfaces of each of the saw blades to form a pair of hardened areas in contact with both ends of the front and rear surfaces and the top surfaces of each of the plurality of saw blades.

The laser heat treatment step may satisfy a laser power of 3 to 4 kW, a progress speed of 2.5 to 3.5 m/min, a focal length of 50 to 150 mm, and an amount of argon gas of 20 to 40 L/min.

The friction saw for cutting high manganese steel according to this embodiment can smoothly cut high manganese steel material with high rigidity and toughness, for example, high manganese steel pipe without defects, due to the arrangement, shape and hardening area of the saw blade, and excellent service life This enables high productivity in the field.

1 is a front view of a friction saw for cutting high manganese steel according to an embodiment of the present invention.
2 is a partially enlarged perspective view of a friction saw for cutting high manganese steel according to an embodiment of the present invention.
FIG. 3 is an enlarged view showing a radial cut surface of the friction saw shown in FIG. 1 .
4 is a schematic diagram illustrating a laser heat treatment step.
5 is an enlarged photograph of a saw blade including a pair of hardened regions formed in the laser heat treatment step.
FIG. 6 is a partially enlarged photograph of FIG. 5 .

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 and 2 are respectively a front view and a partially enlarged perspective view of a friction saw for cutting high manganese steel according to an embodiment of the present invention, and FIG. 3 is an enlarged view showing a radial cut surface of the friction saw shown in FIG. 1 .

1 to 3, the high-manganese steel cutting friction saw 100 according to the present embodiment includes a base 10 made of a disk of a preset thickness, and the base 10 and integrally formed with the base 10. It includes a plurality of saw blades 20 arranged in series on the circumferential surface.

The base 10 and the plurality of saw blades 20 may be made of a cemented carbide material, for example, carbon steel, and may have a preset thickness, for example, a thickness in the range of 5 mm to 10 mm. A plurality of saw blades 20 are positioned on the circumferential surface of the base 10, and are continuously arranged along the circumferential direction. The plurality of saw blades 20 all have the same shape and the same size.

The friction saw 100 for cutting high manganese steel may have the same diameter, thickness, and opening diameter for inserting the rotation shaft as the friction saw for general carbon steel so as to be compatible with the friction saw for general carbon steel. In this case, a high manganese steel material, for example, a high manganese steel pipe can be cut by replacing only the friction saw in a cutting device equipped with a general carbon steel friction saw.

Since high manganese steel has high toughness, it is necessary to increase the cutting force by increasing the cutting area of the saw blade 20 for cutting. Therefore, the plurality of saw blades 20 are continuously positioned without breaking, and do not have passages (concave grooves) for discharging chips.

The base 10 may have, for example, a diameter of 1000 mm, and approximately 300 to 380 saw blades 20 may be arranged along the circumferential direction of the base 10 . The diameter of the base 10 and the number of saw blades 20 are not limited to the illustrated examples and may vary.

Each of the plurality of saw blades 20 is made of a left-right symmetrical triangle, and the vertex and the left-right lower point may be rounded to have a curvature of a preset radius. Each of the plurality of saw blades 20 may have a height h of approximately 6.5 to 7.5 mm, and may be arranged at a pitch p of approximately 9 to 10 mm.

Each of the plurality of saw blades 20 has a front surface 21 , a rear surface 22 , a top surface 23 , and a pair of inclined surfaces 24 . The front surface 21 of the saw blade 20 is connected to the front surface of the base 10, the rear surface 22 of the saw blade 20 is connected to the rear surface of the base 10, the top surface 23 and a pair of inclined surfaces ( 24 is orthogonal to the front surface 21 and the rear surface 22 . The top surface 23 is located between the pair of inclined surfaces 24 and is located farthest from the center of the base 10 .

Each of the plurality of saw blades 20 includes a hardened area 30 for reducing wear rates. The hardened region 30 may be formed by a laser heat treatment process, and has a higher hardness than an uncured region. At this time, assuming that the hardened area 30 is located on the entire saw blade 20, the increased hardness of the saw blade 20 may rather impair the cutting properties of the high manganese steel material, so the hardened area 30 is the saw blade 20 ) is located in part of

Each of the plurality of saw blades 20 includes a pair of hardening areas 30 formed to a predetermined depth on each of the front surface 21 and the rear surface 22 . The pair of curing regions 30 may be located on the entire front surface 21 and the rear surface 22 or a part of the front surface 21 and the rear surface 22 . In the latter case, the pair of hardening regions 30 may be positioned above each of the front surface 21 and the rear surface 22 so as to be in contact with the top surface 23 .

Each hardened area 30 may have a depth that gradually increases from the base 10 toward the top surface 23 , and the maximum depth d of each hardened area 30 is the saw blade 20 thickness (t). less than half of The pair of hardening areas 30 are positioned apart from each other with the central portion of the top surface 23 interposed therebetween, and both ends of the top surface 23 of the saw blade 20 in contact with the front surface 21 and the rear surface 22 are belongs to the hardening region 30 .

The plurality of saw blades 20 are sequentially worn from the top surface 23 toward the base 10 in the course of use. At this time, as the pair of hardened areas 30 support the side surfaces of the saw blade 20 on both the front surface 21 and the rear surface 22 of the saw blade 20 , the plurality of saw blades 20 have the cutting characteristics of high manganese steel material. It is possible to reduce the wear rate without compromising the

The maximum depth d of each hardened region 30 may be between approximately 0.05 and 0.25 times the thickness t of the saw blade 20 . When the maximum depth (d) of each hardening area (30) is less than 0.05 times the thickness (t) of the saw blade (20), the effect of increasing the hardness of the saw blade (20) is insufficient, and the effect of reducing the wear rate of the saw blade (20) is difficult to implement. On the other hand, if the maximum depth (d) of each hardened region 30 is greater than 0.25 times the thickness (t) of the saw blade 20, cutting characteristics may be reduced when cutting high manganese steel with high ductility.

And the hardened area 30 formed by laser heat treatment may have a hardness of about 800 to 890 Hv, and the remaining area (base material) except for a pair of hardened areas 30 of the saw blade 20 has a hardness of about 350 to 420 Hv. can have Since the hardness of the hardened area 30 is approximately twice the hardness of the base material, both sides of the saw blade 20 can be firmly supported.

Next, a method for manufacturing the above-described friction saw 100 for cutting high manganese steel will be described.

The manufacturing method of the friction saw 100 for cutting high manganese steel according to this embodiment includes a friction saw processing step including a base 10 and a plurality of saw blades 20, and a front surface 21 of each of the plurality of saw blades 20 ) and a laser heat treatment step of irradiating a laser to the rear surface 22 to form a pair of hardened regions 30 .

4 is a schematic diagram illustrating a laser heat treatment step. Referring to Figure 4, the laser beam (L / B) is irradiated so as to focus on the front 21 and the rear 22 of the saw blade 20, the friction saw 100 is rotated or the laser light source moves The plurality of saw blades 20 are sequentially heat-treated.

In the laser heat treatment step, the laser power is 3 to 4 kW, the progress speed is 2.5 to 3.5 m/min, the focal length is 50 to 150 mm, and the amount of argon gas may be set to 20 to 40 L/min. 5 is an enlarged photograph of the saw blade 20 including a pair of hardened regions 30 formed in the laser heat treatment step under the above-described conditions.

The depth of each cured region 30 was approximately 500 to 600 μm, and the curing height was measured to be approximately 3,500 to 5,000 μm. Given that the thickness of the saw blade 20 is approximately 8,000 μm and the height of the saw blade 20 is approximately 7,000 μm, the depth of each hardened region 30 corresponds to approximately 0.0625 to 0.075 times the thickness of the saw blade 20, It can be seen that the hardened area 30 is formed on more than half of the front and rear surfaces of the saw blade 20 .

FIG. 6 is a partially enlarged photograph of FIG. 5 . The left part of FIG. 6 is a cured area, and the right part is an uncured part. The results of measuring hardness for 10 points shown in FIG. 6 are shown in the table below. The arrows and the moving direction shown in FIG. 6 mean a direction from the measurement point No. 1 to No. 10.

measurement
Point One 2 3 4 5 6 7 8 9 10 Hardness
(Hv) 846 877 867 861 811 379 377 387 396 410

As shown in the table, the hardness of the uncured region belongs to 379 to 410 Hv, and the hardness of the cured region is 811 to 877 Hv, and it is confirmed that the hardness of the cured region is approximately twice higher than that of the uncured region. Table 2 below shows the experimental results of cutting high manganese steel pipes under various conditions.

experimental conditions Experiment result Comparative Example 1 Use of a friction saw for general carbon steel cutting Defective cutting occurs about 5 times Comparative Example 2 Using a friction saw for cutting carbon steel with a tungsten carbide coating layer Defective cutting occurs about 8 times Comparative Example 3 Using a friction saw having the saw blade shape of FIGS. 1 to 3, but not having a hardened area Cutting defects occurred about 42 times Example Using a friction saw having the saw blade shape of FIGS. 1 to 3 and having a pair of hardened areas on each of the plurality of saw blades Can be cut up to 150 times without defects

As shown in the table, it can be seen that the friction saw of the embodiment was smoothly cut without cutting defects up to 150 times. As a result of observing the saw blade of the friction saw after cutting 150 times, it was confirmed that the saw blade having a height of about 4.5 to 5 mm remained from the initial 7 mm height. High manganese steel pipe with high toughness can be cut smoothly without defects due to over-alignment and hardening area, and sufficiently high productivity can be secured in the field.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and this is also the present invention It is natural to fall within the scope of

100: friction saw 10: base
20: saw blade 21: front
22: rear 23: top surface
24: inclined surface 30: hardening area

Claims (8)

a base made of a disk;
It is integral with the base and includes a plurality of saw blades continuously arranged on the circumferential surface of the base,
Each of the plurality of saw blades has a front surface, a rear surface, a top surface, and a pair of inclined surfaces, and includes a pair of hardening areas in contact with both ends of the front surface, the rear surface and the top surface,
The top surface is located between the pair of inclined surfaces and is located farthest from the center of the base,
The pair of hardened regions have a higher hardness than the uncured regions,
The pair of hardened areas are located apart from each other with the central portion of the top surface interposed therebetween. According to claim 1,
A friction saw for cutting high manganese steel each of the plurality of saw blades is made of a symmetrical triangle, and the vertex and the left and right lower points have a predetermined radius of curvature. 3. The method of claim 2,
Each of the pair of hardened areas has a depth that gradually increases from the base toward the top surface, and the maximum depth of each of the pair of hardened areas is less than half the thickness of the saw blade. 4. The method of claim 3,
Each of the pair of hardened areas occupies more than half of each of the front surface and the rear surface on the upper side of the front surface and the upper side of the rear surface in contact with the top surface. 4. The method of claim 3,
The maximum depth of each of the pair of hardened areas is between 0.05 and 0.25 times the thickness of the saw blade. 6. The method of claim 5,
The pair of hardened areas have a hardness of 800 to 890 Hv, and the other areas of the saw blade except for the hardened area have a hardness of 350 to 420 Hv. A processing step of machining a friction saw comprising a disk-shaped base and a plurality of saw blades continuously arranged on the circumferential surface of the base and each having a front surface, a rear surface, a top surface, and a pair of inclined surfaces; and
A laser heat treatment step of irradiating a laser to the front and rear surfaces of each of the plurality of saw blades to form a pair of hardening areas in contact with both ends of the front and rear surfaces and top surfaces of each of the plurality of saw blades,
The top surface is located between the pair of inclined surfaces and is located farthest from the center of the base,
The pair of hardened regions have a higher hardness than the uncured regions,
The pair of hardened areas are located apart from each other with the central portion of the top surface interposed therebetween. 8. The method of claim 7,
The laser heat treatment step is a method of manufacturing a friction saw for cutting high manganese steel that satisfies a laser power of 3 to 4 kW, a progress speed of 2.5 to 3.5 m/min, a focal length of 50 to 150 mm, and an argon gas amount of 20 to 40 L/min.

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